WBO lightweight champion Ricky Burns' unification title fight with IBF belt-holder Miguel Vazquez has been delayed by a month due to the Mexican suffering from a severe viral infection.

The pair were set to meet for their respective crowns on March 16 at Wembley Arena, but Vazquez's illness has forced Burns' promoter Frank Warren to postpone the event which was also set to feature WBO light-heavyweight champion Nathan Cleverly.

The British pair will now headline the show at the same venue on Saturday, April 20.

Warren said on his official website: "It's very unfortunate that Vazquez has had to withdraw so close to the fight, but it is on medical grounds, which is beyond my control, due to his viral infection, and we have his doctor's certificate confirming this.

"Therefore I have had to postpone the fight, not cancelled as stated in some media reports, to Saturday 20th April at Wembley Arena.

"Everybody is disappointed by this postponement, but we have worked hard to ensure that Ricky's unification fight still goes ahead."

This is not the first time the Scot, who impressively stopped Kevin Mitchell inside four rounds in his last fight, has endured frustration ahead of a scheduled bout.

He was due to face Liam Walsh in London in December but his opponent pulled out after a car accident. His replacement, Jose Ocampo, then withdrew just days before fight night.

The two-weight world champion (35-2, 10KO wins) has been left distinctly unimpressed with the latest turn of events.

After rumours of the fight being cancelled were spread, Burns' manager Alex Morrison told the Scottish Sun yesterday: "While there is talk of it being rescheduled within 30 days, Ricky and I are very unhappy."

There was the option of finding a replacement opponent but it is understood Burns craved the unification fight in order to head into a possible bout with WBC champion Adrien Broner in a strong position.

Cleverly was due to defend his world light-heavyweight title against Robin Krasniqi but a statement on Warren's website revealed the Welshman may have struggled to fight in two weeks' time.

It read: "Cleverly will also welcome the postponement as he has been suffering from a stomach virus that left him unable to train for five days last week and then when he resumed training he relapsed again.

"This will ensure that he is back to full fitness for the new date."

Controversial heavyweight Dereck Chisora is also scheduled to compete - provided he receives his British Boxing Board of Control license - in his first bout since being stopped by fellow Londoner David Haye last July.

That contest was sanctioned by the Luxembourg Boxing Federation after Chisora's British licence was withdrawn due to the pair's infamous brawl in February last year.